Obesity Surgery

, Volume 23, Issue 9, pp 1427–1430 | Cite as

Estimating Renal Function in Morbidly Obese Patients

  • Alex Lovell
  • Philip Game
  • Gary Wittert
  • Campbell Thompson
Original Contributions



This paper aims to evaluate, in a clinical context, current creatinine-based formulas commonly used to calculate renal function in morbidly obese patients.


A retrospective analysis was performed of the estimates of renal function of 63 obese or morbidly obese patients undergoing gastric bypass surgery. Each patient’s glomerular filtration rate (GFR) was calculated using five methods, both before and after surgery, and these approximations were then compared.


Prior to surgery, the values offered by the five formulas for the renal function of this population ranged widely, by over a factor of 2. After surgery, the three weight-based GFR estimation methods indicated that a significant change in GFR had occurred, but the two non-weight-based formulas showed no significant change in estimated GFR.


At baseline and after significant weight loss, creatinine-based formulas differ twofold in their estimates of renal function of the morbidly obese. An accurate method for calculating these patients’ renal function is required to improve patient safety with drug dosing as well as to ensure early detection of renal failure.


GFR MDRD Weight loss Surgery 



Glomerular filtration rate


Modified diet in renal disease


Cockcroft–Gault formula


Body mass index


Body surface area


Ideal body weight


Salazar and Corcoran formula


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Alex Lovell
    • 1
    • 3
    • 4
  • Philip Game
    • 2
  • Gary Wittert
    • 1
    • 2
  • Campbell Thompson
    • 1
    • 2
  1. 1.University of AdelaideAdelaideAustralia
  2. 2.Royal Adelaide HospitalAdelaideAustralia
  3. 3.University of Adelaide, Royal Adelaide HospitalAdelaideAustralia
  4. 4.BroadviewAustralia

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